Not sure how the resistor currently functions but my initial idea would be increase normal force between two disks (one fixed one rotating) because the frictional force grows roughly linearly with normal force. You can get a normal force that varies linearly by compressing a spring attached to the fixed disk. All that would be left would be to figure out how to adjust the compression of the spring with a knob which seems feasible using some screw like mechanism.
While this is cost effective, I think it would run into one of the problems @pgboswell found in making the regular resistors- since, as mentioned, frictional force is proportional to normal force, that means that frictional force is also proportional to spin voltage, meaning that resistance would begin to drop linearly as voltage increases and vice versa.
The way resistors currently work is that they use shearing of silicone oil, a highly viscous newtonian fluid. What if there was a dial/plunger that raised or lowered the level of the oil, thus changing the amount of it in contact with the bearing surface? Keeping it watertight would be the main issue, but the mechanism for raising and lowering would be similar in complexity.
On ICs: the talk of Op-Amps above made me think of the 555 timer, but something tells me that would be either incredibly fun or nightmarishly difficult to design. For something less ambitious, it would be great to have ICs for signal processing, as that would create a wide range of interesting puzzles while relating to real-world educational topics, from RF to analog computing. I imagine a clock generator and wave generator would be quite simple and useful. With a bit of inspiration from old naval artillery computers, it might even be possible to make compact switch-programmable ROM chips, or even individual modules for basic analog computing arithmetic!
As for outputs: I had an idea for a Spintronic light, but with a bit of departure from pure mechanics- I imagined a gaslamp with a shade that could be raised or lowered, which would be very steampunk. Of course, an actual gas lamp would be comically unsafe for a children’s toy, so a more sane option would be a dynamo powered LED, which could either be wound up before hand, or perhaps even powered by the circuit itself, presenting an interesting challenge.
what if you used 2 magnetic planes that rotate wit a knob. at 0 they are parallel abd would have 0 resistance. when the knob is adjusted the magnetic flux begins to opose eatch other causing resistance to the driving mechanism.
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Function generator for more convenient alternating current
that would be neat even if it was only avaliable in the simulator. would love to observe the effects inductive and cappasitive reactance.
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I was thinking about a AC source to mimic the power outlets in your home. It would help for educational reasons to show the differences between batteries and power outlets.
Act 2 seems to make a lot of oscillators, so I think it makes sense to continue with those. Not sure what the possibilities would be.
thoe that would be cool. I dont think it will be possibe using the curent 6 v power suply.
it would probably have to be battery powered or gravity driven similar to a grandfather clock.
if internal friction of the gears(resistance) is ignored their is power requierment to maintain the ocsilation. For simplicity this is called leakage current .
Look up transformer equivlent circuits. this should give you an idea and a good chalange to try to make a work around.
a Power factor corection method would be needed as one way to reduce the effects of the inductive load. both to save as much of the stored energey as posible and to keep the system mooving smoothly.
mechanical engineering wasnt my field of study, so im not even sure if or how to mesure the extent of or how to wrap my head around anular velocity lagging behind positive force in a mechanical system. My best guess would be significant stress on the internal gears of the power suply therby causing even more resistance.
any attemp to correct for power factor would likley negate its intended purpose as well bing that the junctions will face the same effect.
Having gotten into the later part of Act 2, I’d like an AC power source too! It could be done simply (famous last words) by adapting a reciprocating gear mechanism to drive a sprocket a fixed distance (Spin watt?) clockwise, then counterclockwise. Come to think of it, with a cam-and-follower, it could even be a kind of fixed function generator…
EDIT: The mechanism in that video would produce a triangle wave AC generator. A scotch yoke would produce a more sinusoidal waveform, with the benefit of controlled amplitude.
I had an idea for a very simple part, to solve a very annoying problem- getting belt tension just right. I’m looking to 3d print a prototype for my own use, but haven’t made a model for it yet- the “Belt Tensioner”. Effectively the same as a 0-Ohm resistor or the level changer in the simulator, but instead of being fixed to the magnetic base like all the current components, it’s on an arm that can be “extended”. This would allow it to be adjusted a bit more carefully than nudging a closed switch or similar.
You mean a derailleur?
https://en.wikipedia.org/wiki/Derailleur#/media/File:Shimano_xt_rear_derailleur.jpg
Essentially, but without the sprocket changing. (though, I wonder what creative uses being able to dynamically change levels would bring…)
So like this chain tensioning module on this single-speed bicycle.
(picture is public domain from wikipedia)
It might take a little work, but a spin oscilloscope would be helpful. My daughter and I just received our spintronics lastnight and we made a rectifier. Tonight we added a filter to smooth the output. I suspect it wouldn’t be too difficult to create, perhaps a drum based 'scope using a felt marker on paper. The drum would spin based on a clockwork, perhaps the spintronic’s power supply, appropriately regulated, and the deflection would of course be based on the spin voltage. Would make the half, full wave rectification, as well as filter tuning all the more tangible. Congratulations for bringing such a complex idea successfully to market! I am envious of the generations of kids who will build profound intuition having experienced your models. Thank you!
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How about an equivalent to an LED that raises an indicator while current is flowing and drops the indicator when current stops?
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I realize this might go against the “all mechanical” philosophy of Spintronics (which I do think is awesome), but I found myself wanting a “battery” that was actually electrically powered (preferably plugged into the wall, rather than running on “battery batteries”), so I could leave a circuit running as an interesting piece of office art. Maybe there are also non-philosophical reasons why this would be a headache (perhaps a risk of mechanical damage while running unattended?), but I thought I might as well make the request.
I’ll second the request for some sort of paper plotter to show voltage and/or current over time!
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Of the pieces I’ve worked with the ampèremeter is my least favourite. The idea of a grammophone is nice. But the sound is annoying, the difference in sound is different to hear and it’s not quantitative like the voltagemeter.
My idea is to measure the rotational speed by placing a bowl with a marble on top of the gears. The rotation is pushing the marble outward and gravity pushes it down. By giving the bowl a curve, you create an equilibrum position for a given speed. By printing lines on the inside you can measure speed quantitatively.
Now, I don’t know what dimensions this bowl/whirlpool will become, but it’s an idea to explore. Maybe the lane in which the marble can roll will need to be fixed.
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Couldn’t help thinking about this a bit more, and have a few more suggestions…
First, some fairly straightforward mechanical ones that are still worth mentioning:
- A dedicated level changer, like the one in the simulator
- A push button, i.e. is on only while it is pressed (useful for any circuit with latch/reset behavior)
- I only just got my head around the three-way junction, so I don’t know what’s possible here, never mind practical, but a four- or five-way junction seems like it could declutter some circuits (presumably with some gears sharing levels)
- Something like a (resettable) analog odometer, which could measure total charge flowing through a part of the circuit (I don’t know if it would be practical to measure the total energy by also detecting the voltage); bonus points for making it look like a part of Babbage’s Difference Engine
- Mechanical counter that detects number of pulses (same bonus; more appropriate here, really)
Next, a few electrical/electronic components I haven’t seen mentioned:
- A Zener diode, i.e. current starts to flow past a certain voltage (may or may not be a diode in the other direction – perhaps the Spintronics version has the “breakdown” behavior in both directions?)
- A transformer that allows winding/gear ratios other than 2 or ½
- A large capacitor that can actually store a decent amount of the battery’s input energy (not entirely sure this is useful, but maybe it’s more practical in some circuits than “leaving the energy in the battery for later use”)
Third, sensors. Light and sound sensors are clearly impractical unless you involve electronics (um, see below). An accelerometer might be practical, but this would presumably require something like the aforementioned “steampunk chassis” in order to be useful. That leaves:
- A pressure sensor – could even be used to build a simple scale?
- Temperature sensor – probably much harder to build reliably, but it would be cool to see a bimetallic strip incorporated somewhere
Finally, since I “went there” with the plug-in battery (or “electrical/mechanical energy converter”) suggestion:
- A “smart block” with a tiny screen and simple programmable microcontroller. Would presumably draw power from the plug-in battery. Obviously extends Spintronics in a fairly radical direction, but I do think it’s interesting to demonstrate conversion between different kinds of logic. There are a lot of toys in this space, but maybe this smart block could be compatible with some of them, in which case the toys could then be used together (and alternately, maybe the “smart” block doesn’t actually need to be smart or have a screen, just interface to something that does).
The parallel magnetic planes solution to the variable resistor sounds great. There’s so much you can do with that trick. I hope @pgboswell tries this out.
The only current form of input is the switch. I don’t know if it is possible but a potentiometer would be very nice to have.